JPH0529806A - Branching and synthesizing device - Google Patents

Abstract

PURPOSE:To suppress the increase of an insertion loss and to easily obtain an excellent passage characteristic even if the number of band pass filter is increased. CONSTITUTION:Band-pass filters 111 to 14 for performing branching of the signal components of frequencies f1 to f4 are connected with the branching end of a reactance branching circuit 21, respectively. The one end of the reactance branching circuit 21 is connected with a reflection end 1b of a circulator 1. Similarly, band-pass filters 15 to 18 for performing branching of the signal components of frequencies f5 to f8 are connected with the branching end of a reactance branching circuit 22, respectively. The one end of the reactance branching circuit 22 is connected with a reflection end 2b of a circulator 2. When a signal is inputted in an input end 1a of the circulator 1, the signal components of the frequencies f1 to f8 for which the branching were performed via the band-pass filters 11 to 18 can be obtained, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a demultiplexing / synthesizing device, and more particularly to a demultiplexing / synthesizing device applied to a microwave radio communication device.

[0002]

2. Description of the Related Art A first example of a conventional demultiplexer / synthesizer is shown in FIG.
, The circulators 31 to 31 are connected in cascade.
38 and a band pass filter 41 having different pass bands from each other.
To 48 are combined. The figure also shows a case where eight band pass filters are used to function as a demultiplexer, and the input end 31a of the circulator 31 is shown.
The signals input to the circulators 31 to 38 are respectively passed by the bandpass filters 41 to 48 connected to the reflection ends of the circulators 31 to 38.
The signal components of frequencies f1 to f8 are demultiplexed.

Here, of the signals input to the input end 31a, the signal component of the frequency f1 is output via the bandpass filter 41 connected to the reflection end of the circulator 31. On the other hand, the signal components other than the frequency f1 are reflected by the band pass filter 41, input to the circulators 31 to 32, and then similarly demultiplexed.

When functioning as a synthesizer,
Signals are input from the band pass filters 41 to 48, respectively, and the combined signal is extracted from the output end of the circulator 38.

As a second example of the conventional demultiplexing / synthesizing device, as shown in FIG. 3, a reactance branch circuit 51 is used in place of the circulator. At the branch end of the reactance branch circuit 51, the bandpass filter 41 is provided.
~ 48 are connected respectively.

[0006]

In the above-mentioned first example of the conventional demultiplexing / synthesizing device, since a large number of circulators are used according to the number of demultiplexing, there is a problem that the insertion loss increases due to the passage loss of the circulator. is there.

In the second example, the circulator is not used, which is advantageous in that the size and the loss are small. However, the reactance branch circuit has the reflection phase characteristic of the bandpass filter connected to each branch end. As a result, the pass characteristics of other band pass filters are affected. Therefore, when the number of band pass filters is increased to about 8, phase adjustment becomes very complicated, and it becomes difficult to obtain good pass characteristics. There is.

An object of the present invention is to provide a demultiplexing / synthesizing device capable of suppressing an increase in insertion loss even if the number of bandpass filters is increased and easily obtaining a good pass characteristic.

[0009]

A demultiplexing / synthesizing device of the present invention has at least three terminals of an input end, a reflection end, and an output end, and a plurality of cascade-connected by the input end and the output end. A circulator; a plurality of bandpass filters having different passbands; one end connected to each reflection end of each of the plurality of circulators, and each bandpass filter connected to the other end branched into a predetermined number A plurality of reactance branch circuits;
A signal is input to the input terminal of the circulator of the first stage among the plurality of circulators connected in cascade, and the demultiplexed signals are respectively extracted from the plurality of band pass filters. Further, it is configured to input a signal to each of the plurality of band pass filters and take out a combined signal from the output end of the circulator at the final stage among the plurality of cascade-connected circulators.

[0010]

The present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention and shows a case where eight band pass filters are used to function as a demultiplexer.

The circulators 1 and 2 have input ends 1a and 2a, reflection ends 1b and 2b, and output ends 1c and 2c, respectively, and the output end 1c and the input end 2a are connected in series. It is connected. Further, a terminating resistor 26 is connected to the output end 2c.

Bandpass filters 11 to 14 for demultiplexing the signal components of frequencies f1 to f4 are connected to branch ends of the reactance branch circuit 21, and one end of the reactance branch circuit 21 is connected to the circulator 1. Is connected to the reflection end 1b. Similarly, frequencies f5 to f
Band pass filter 15 for demultiplexing 8 signal components
18 are respectively connected to the branch ends of the reactance branch circuit 22, and one end of the reactance branch circuit 22 is
It is connected to the reflection end 2b of the circulator 2.

The signal input to the input terminal 1a of the circulator 1 passes through the circulator 1 and is input to the reactance branch circuit 21. Here, frequencies f1 to f4
The signal components of (1) are demultiplexed through the bandpass filters 11 to 14, respectively. On the other hand, the signal components of frequencies f5 to f8 are reflected by the bandpass filters 11 to 14 and return to the reflection end 1b of the circulator 1. Then, it is input to the input terminal 2 a of the circulator 2 and then input to the reactance branch circuit 22. Here, the frequency f5 to f48 signal components are demultiplexed through the band pass filters 15 to 18, respectively.

Assuming that the pass loss per pass of the circulator is 0.2 dB, the pass loss of the reactance branch circuit is 0.1 dB, and the insertion loss of the band pass filter is 1 dB, the loss for the signal component of frequency f8 is 0. .2 × 3 + 0.1 × 3 +1 = 1.9 dB (circulator) (reactance branch circuit) (BPF).

By the way, in the conventional case shown in FIG. Therefore, the demultiplexing / synthesizing device of this embodiment has less loss than the conventional one.

When functioning as a synthesizer,
It suffices to input signals from the band-pass filters 11 to 18 and take out the combined signal from the output end of the circulator 2.

[0018]

As described above, according to the present invention, a circulator and a reactance branch circuit are provided so as to correspond to each other, and the number of bandpass filters connected to each reactance branch circuit is limited to adjust the phase of the reactance branch circuit. It becomes easy, and it becomes possible to obtain good pass characteristics. At the same time, since the number of circulators used can be reduced, insertion loss can be reduced and the size can be further reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a first example of a conventional demultiplexing / synthesizing device.

FIG. 3 is a block diagram showing a second example of a conventional demultiplexing / synthesizing device.

[Explanation of symbols]

1, 2 circulator 1a, 2a Input end 1b, 2b Reflection edge 1c, 2c output end 11-18 Band pass filter 21,22 Reactance branch circuit

Claims (2)

[Claims] 1. A plurality of circulators each having at least three terminals of an input end, a reflection end, and an output end, and cascaded by the input end and the output end; and a plurality of bandpasses having different pass bands from each other. A plurality of reactance branch circuits each having one end connected to a reflection end of each of the plurality of circulators and each of the bandpass filters connected to the other end branched into a predetermined number; A demultiplexing / synthesizing device, wherein a signal is input to the input end of a first-stage circulator of the plurality of circulators, and the demultiplexed signals are respectively extracted from the plurality of bandpass filters. 2. The demultiplexing / synthesizing device according to claim 1,
Input signals to the plurality of band pass filters,
A demultiplexing / synthesizing device, wherein a synthesized signal is taken out from the output terminal of the circulator at the final stage among the plurality of circulators connected in cascade.